In case you are concerned about other platforms that Kotlin supports (Kotlin/JVM for server and desktop, Kotlin/JS and Kotlin/Native), please be sure that they are as important for us as ever. Our vision here is to make Kotlin a uniform tool for end-to-end development of various applications bridging multiple platforms with the same language. ... First-class support on Android will likely bring more users to Kotlin, and we expect the community to grow significantly. This means more libraries and tools developed in/for Kotlin, more experience shared, more Kotlin job offerings, more learning materials published, and so on. We are excited to see the Kotlin ecosystem flourish!

An interesting point related to and included in this announcement is mentioned in the Kotlin on Android FAQ:

What's the future of Kotlin? JetBrains' thoughtful work on Kotlin's design is one of the reasons we're embracing the language. Google is partnering with JetBrains to ensure a wonderful overall developer story—from language, to framework, to tools. And, we are excited to be working together to move the Kotlin language into a non profit foundation.

The Kotlin blog post describes the future of Kotlin with Android in greater detail:

We will be partnering with Google to create a non-profit foundation for Kotlin. Language development will continue to be sponsored by JetBrains, and the Kotlin team (over 40 people and second largest team at the company) will operate as usual. Andrey Breslav remains the Lead Language Designer, and Kotlin will be developed under the same principles as before.

In the 2016 edition of my annual post on significant software developments of the year, I listed Kotlin-related developments in the "Honorable Mention" section. With this announcement of Kotlin being officially supported on Android and the language being placed in nonprofit foundation and enjoying support of Google and JetBrains, I think it's very possible that Kotlin will make my top ten list in 2017 for significant software language development developments. Besides these announcements, Kotlin has already seen JavaScript support released in Kotlin 1.1 in 2017 and a preview of Kotlin/Native.